The present invention relates generally to an improved cleaning cartridge for cleaning the read/write head of a computer data backup drive, and more specifically to cleaning the air bleed slots in a read/write head.
The subject matter of U.S. Pat. No. 5,541,794 contains a detailed disclosure of a cleaning cartridge of the type discussed herein, and is hereby incorporated by reference. Typical tape backup drive systems employ a magnetic media recording tape, the read/write head of the tape drive, and firmware within the tape drive for initiating proper operation of the drive for backup and for cleaning purposes. Magnetic media used in computer data backup tapes have traditionally been constructed of an elongated tape coated with ferric oxide. Recently, backup tapes using a media coating of metal particles have become common. All magnetic media containing coatings have a tendency to generate debris during usage. Magnetic media having metal particle coatings typically shed more debris than ferric oxide magnetic media coatings.
Traditionally, tape drive read/write heads have had contours on the media-contacting portion of the head consisting of smooth bumps with ramps. Recently, many tape drive read/write heads have begun to use heads with media-contacting portions of the head having bumps with sharp edges. These new read/write heads also contain a plurality of substantially vertical slots, known as air bleed slots, which assist in the provision of good read/write head to media tape contact.
Typical magnetic media tape speeds across a read/write head range from 90 to 120 inches per second. When the media tape is moving with such high speed across a read/write head, air may become trapped between the tape and the read/write head, creating an air bearing which adversely affects the quality of contact between the tape and the read/write head. The substantially vertical air bleed slots of a new type read/write head are aligned substantially perpendicular to the direction of motion of the media tape past the read/write head. The sharp edges of the air bleed slots effectively cut the air build up between the read/write head and the tape. The air bleed slots serve to allow this cut air to be dissipated from between the read/write head and the media tape through the slots, allowing a more consistent head to tape contact.
It is well known that a build up of debris within a tape drive can lead to decreased performance and even damage the tape drive. Some of the debris shed by the magnetic media accumulates in the air bleed slots. When these slots become partially or fully filled with debris, they are no longer effective in allowing cut air to bleed away from the interface between the magnetic tape and the read/write head. When this happens, the quality of contact between the tape head and magnetic media is compromised. Traditional cleaning tapes move across the read/write head of a tape drive in a direction substantially perpendicular to the vertical slots. During a cleaning operation, firmware for the drive causes the read/write head to reciprocate vertically up and down. However, even this vertical reciprocation does not allow effective cleaning of the air bleed slots by the cleaning tape because the cleaning tape does not penetrate into the slots. Accordingly, a conventional cleaning tape is inefficient to fully clean the read/write head of a tape drive when the read/write head contains air bleed slots.
One problem that cleaning cartridges have largely failed to overcome is being able to accommodate different models of magnetic media recorders/players. Though the size of the read/write heads are relatively standard, small differences are often experienced in the distance the heads travel when engaging a cassette cartridge. For purposes of simply playing or recording a tape, these small differences are largely inconsequential. However, cleaning cartridges, such as the one described herein, can also employ brushes or cleaning elements in addition to a spool of cleaning tape. In order to make contact with the read/write head, a stationary cleaning element must be located the proper distance from the head such that, when the head completes its engaging travel, the head comes in contact with the elements enough to effect cleaning of the head, but not so much that the tape passing between the head and the cleaning elements experiences excessive friction.
It would therefore be desirable to provide a cleaning cartridge capable of not only cleaning the surface of the read/write head of a tape drive, but also its air bleed slots.
It would also be desirable to provide an apparatus to clean the air bleed slots of a read/write head, wherein the apparatus may be used with existing tape drive cleaning cartridges.
It would also be desirable to provide an apparatus for cleaning the surface and air bleed slots of a read/write head which is capable of tolerating minor differences in the read/write head travel distances of various tape drives.